A. c. switch with knob actuation



DeC- 14, 1954 v. R. DEsPARD A.C. SWITCH WITH KNOB ACTUATION Filed Nov. 7, 1952 f E \\\v VISTO 1.. G I F,

f, l /l United States Patent O A. C. SWITCH WITH KNOB ACTUATION Victor R. Despard, Syracuse, N. Y., assignor to Pass & eyrlrlour, Inc., Syracuse, N. Y., a corporation of New Application November 7, 1952, Serial No. 319,249

7 Claims. (Cl. 200-6) The invention relates to flush or wall mount electric switches, and more particularly to such switches of the alternating current, slow-break type actuated by an oscillatable knob.

It is a general object of the invention to provide a novel and improved switch of the type described.

More particularly it is an object of the invention to provide, in a switch of the type described, a novel arrangement for and mounting of fixed and movable contacts.

Another object resides in the provision of a unique mount for the switch operator over-center spring incorporated with a terminal plate and conductor strip.

Among the unique features of the invention may be enumerated the following:

Alternative useof compression or tension spring for over-center operation.

Arrangement of single or dual contact sets for operation transversely of the housing.

Use of the contact springs to cushion the switch operator to a stop at the end of its stroke in either direction.

Disposition of the over-center spring longitudinally of the housing.

Support of the stationary contacts against opposite side walls of the housing.

Other and further objects and features of the instant invention will become more apparent to those skilled in the art as the disclosure proceeds in the following specication and accompanying drawings wherein are disclosed several exemplary embodiments of the invention with the understanding that such changes therein and combinations thereof may be made as fall within the scope of the appended claims without departing from the spirit of the invention.

In said drawings:

Fig. l is a longitudinal central section, taken through the axis of knob rotation, of an A. C. switch of the slowbreak, rotary knob-actuated type constructed according to the present invention',

Fig. 2 is a transverse central section thereof taken on line 2-2 of Fig. 1;

Fig. 3 is a top plan view thereof with the cover removedand showing the switch operator in section on line 3-3 of Fig. l;

Fig. 4 is a view similar to Fig. 2 but depicting a single pole switch with a non-contact-carrying spring blade;

Fig. 5 is a fragmentary view similar to Fig. 1 but illustrating an embodiment using a tension type over-center spring for the switch operation; and

Fig. 6 is a diagrammatic showing of a further embodiment using a single spring blade in a double throw switch.

The switch of the present invention is primarily intended for but not necessarily limited to use in wall and switch boxes for general interior wiring for illumination and like loads, and may be mounted in multiple with like or other wiring devices in a single gang box in a known manner, being supported from a strap or bridge plate as clearly indicated in my earlier Patent 1,992,059, granted February 19, 1935. In order to permit of this use, the switch is provided with a suitably sized and shaped housing of molded insulating material having a closed bottom wall 11, solid side walls 12, and similar end walls 13 and 14, the tirst having a single opening 15 near the bottom and the latter two such openings 16 and 17 lseparated by horizontal partition 18. These three v 8 openings are to provlde access to terminal screws, as

will be later described. The housing top is open to provide access to a relatively large, generally rectangular chamber 19.

The switch illustrated in Figs. l to 3, inclusive, is what is known in the industry as a three-way switch, but is actually a single-pole double-throw switch. The contact structure therefor is extremely simple and comprises two similar sets of contacts each including a stationary contact button 20, 20' and a movable contact button 21, 21'. Each stationary contact button is arranged at the outer end of an offset strap 22, 22', each being formed integral with its corresponding terminal plate 23, 23. These latter are vertically separated by an insulating strip 24 and the whole assembly is received in channels 25 in the housing side walls adjacent end wall 14, as clearly seen in Figs. l and 3. Each terminal plate is equipped with a terminal screw 26, as seen, for the attachment of conductor wires thereto. The straps 22 and 22 are offset one upwardly and the other downwardly and are bent in at right angles from the ends of the terminal plates, as clearly seen in Fig. 3. In this ligure the outer ends of the straps are seen to be offset outwardly so that they rest against a pair of spaced runners 27 formed integral with the housing wall and having sloping upper ends 27. The straps are tightly held against the runners by bolsters 28, extending upwardly from the housing bottom as seen in Figs. l and 3. Thus the stationary contact buttons are secured rigidly in position against movement in any direction.

The movable contacts 21 and 21 are carried respectively on the cantilever arms 30 and 30 of a U-shaped spring having a hat base portion 31. The arms of the spring converge toward the top so that the movable contacts are biased toward open position, as seen at the left of Fig. 2. The U-shaped spring is positioned by and connected to terminal plate 32 arranged adjacent opening 15 in end wall 13. This plate has a iiange portion 33 along its upper edge to offset vertical portion 34 whose ends are extended vertically as legs 41 to t in grooves 35 in the side walls as seen in Figs. 3 and 4. Parallel arms 36 and 37 spring, respectively, from the top and bottom of plate 32, arm 37 extending along the bottom of the housing and beneath the base of the U- shaped spring and being mechanically and electrically connected thereto by rivet 38. This positions the spring so that its contacts are in spaced conforming relationship to the stationary contacts. The arms 36 and 37 are respectively provided with openings at 39 and 40 in vertical alignment with each other for a purpose to later appear.

The slots 35 in the side walls are filled to the top of the housing with the terminal and insulating plates 23, 23' and 24 at one side and by the legs 41 on the other.

The terminal and insulating plates are held in position and the housing closed by a cover plate 42 extending across the whole area of the top thereof. This plate is maintained in position by a metal collar and strap combination 43 which serves to fasten the two portions of the housing together. The cover has a centrally positioned protruding neck 44 equipped with notches 45 for attaching the same to the mounting strap as previously mentioned. The neck is centrally bored to journal the knob used for manipulating the switch. This knob is preferably more or less cylindrical and may be longitudinally uted on its exposed surface to improve the finger grip. It is of relatively small diameter and small protrusion beyond the face of the neck, which is normally hush with the wall plate. Formed integrally with the inner end of the button is a larger diameter ange or disc 51 chamfered on its upper edge and closely received in a correspondingly shaped counterbore 52 in the neck to act as a thrust bearing to prevent the knob from being withdrawn. In some embodiments the knob may be provided, above the flange, with stop lug 54 seen in Fig. l, operating Ain an arcuate channel, the ends of which provide stops to limit knob oscillation. The total range of oscillation isnot greaterthan twenty-five degrees.

Extending downwardly from the knob is the switch operator comprising metal strip 56, reduced in width at 0 the lower end to provide a bearing received in a suitable notch 57 in the bottom of the housing, as seen in Fig.A 3.

Stamped from the metal of the plate 56 is the twisted crank arm 58 notched at its outer end to receive the incurved portion 60 of one leg of a U-shaped spring whose opposite leg 61 passes through and is supported in the openings V3 9 and 4@ in the :parallel VVarms extending from terminal plate 3'2, as clearly seen in Figs. l to 3. The spring is biased to the shape shown and because of its position in respect to the switch operatortends to throw Athe crank arm 58 to one side or the other in what is termed herein an over-center action. operator canonly temporarily maintain a position other than at one of the ends of its range.

-For moving the free ends ofspring arms 30, 36'-, which terminate just beneath the under surface of the `disc l, this disc is provided 'with depending lugs, three in number as seen in Fig. 3. The center one 65 of these lugs is the circnit closing Yone and depends a greater distance 'than lth'eoth'er two, as seen 'in Figs. l and 2, and has a Curved, slightly pointed lower end. The other t'Wo lugs, 66, 66 are of similar but opposite 'disposition and 'all Igs are at the periphery of disc l51 'and are spaced apart a considerable distanee so 'that one of the outer lugs and ythe principal lug form a str'addling 'relationship to each of the free ends of the contact button carrying springs. As viewed in Fig. 3, the principal operating lug v65 is in engagement with spring 30 and has flexed it to the extent that its oontact 21 is in electrical 'engagement with stationary eont'actZlL thus 'closing 'one circuit. At the same 'time lug 65 is well removed from the free end of 'spring 35 which by its own resilience has withdrawn its contact from stationary Contact button Reliance, however, 'is not placed solely on 'the resilience of springs and to separate the c'io'n'tacts, since there is the possibility 'ofwelding 'or sticking. This explainsthe ypurpos f auxiliary operatinglugs 66 and 66 which are "so positioned that as 'principal lug 65 flexes one spring yto closing Positionthe following auxiliary lng engages the other spring 'and forces and 'maintains separation of its contacts, against any possibility of jarring or Ivibrating to closed position. The principal lug "65, in what 'may be termed a neutral position, which of course can never be maintained exceptby holding the knob, is exactly between the arms of the 'LJ- shaped lspring and thus is in position to engage 'each of them at the best possible angle. Note thatwh'en engaged the lug Contact centers transvel-sely of the spring.

Lug 54 on knob 50 'coming in contact 4with the endsuof its groove serves as a positive stop at each end of the knob stroke, yet this is only a secondary safeguard since actual stopping of the knob is eirected in a resilient 'man'- ner by the principal lug 65 which is in engagement with one of the other of the arms o'f the U-shaped spring and serves lto flex the vspring above 'the engaging "contacts, as seen, for instance, at 70 in Fig. 2, thereby bringing the knob to a quiet stop.V 'This form of stopping the knob f insures against any substantial noise in the operation ot the 'switch and if the lingers are held on 'the knob until it reaches the `end of the stroke, operation lcan be almost entirely silent. v

This feature of stopping the yknob yby spring action 4is 'rnade useof where only a single pole fswitch is desir`ed, as illustrated in Fig. 4. Here the arm 30 of the U-sha'ped spring is fitted with a contact button as in 'tlreprevious "embodiment, but the other arm 139 of the spring has no button nor is there a stationary one. in order that the spring 'may stopl against something it is provided with an are'uate onset 131 to engage against the ribs 27 on the wall of the housing to stop the spring in about the same `position thecorresponding one is stopped by contact 'engagement, Thus th'e feel yand operation of this embodiment, in its simpler form, is substantially the same as in Athe other or more eomplexswit'ch. Obviously in this v'e'rnbodimen't one of the terminal plates at the end 1 6 of Ythe housing is omitted and its place taken by a blank of insulating 'rr`1'ater ial. y

The spring 60, 61 formed of piano wire or the like to generally a U-s'h'ape with one long and one short leg is a compression spring. n cases where a tension spring is de- 'sired for one reason or another theswitch operating member maybe altered as illustrated in Fig. 5, where the metal strip 156 is shown as equipped with a crank portion 157 having a narro'iv notched cra-nk `pin158around which 'the loop 'of helical tension spring' 160 is fastened. The other end 'offthis vspring is loopediabont a transverse rod 161 of insulating material, the ends of lwhich are housed Thus the switch in the bottoms of channels 16 2 formed in the facing or inner walls of the holsters 28. This spring has over-center action like the compression -spring of the other figures and is in some cases simpler to assemble. Because of its greater length it gives a somewhat smoother action, changing less in relative length from central to end position than the compression type spring.

The U-shaped spring of the previous 'embodiments can be eliminated by the construction of Fig. 6 and both contact b'ttofns secured, 25o having a foot l231 for attachment to the terminal plate strap; In this form the knob disc needs but two operating lugs 265, 265. The form of spring saves a small amount'of metal but is more diiiicult to make because 'of the diie't'llty of brani-ng' or soldering the silver contact buttons onto the bronze spring.

It will be noted that each movable contact button is positioned substantially at a nodal point in the length of its cantilevered spring arm to produce a minimum of vibration or chattering during 'the closing operation. This closing operation is relatively slow, as is the opening one, because of vthe manual manipulation of the switch 'operator, which is not under control solely of the spring. When the operator moves to Iits `over-center position and engages the contacts, contine'd movement liexes the upper vend of the cantilever spring and rocks the contacts to insure their self cleaning and their tight engagement, which is eliminated by the over-center spring, as will be appreciated. n

The construction just shown and ydescribed provides a 'switch which is small in size, relatively cheap 'to construct, effective in operation and 4which provides increased cui'. rent carrying capacity with a relatively small number of simple parts.

I claim:

l. A slow-break, A. C. switch comprising, in combination, 'a housing vof 'rectangnlar configuration having side and end walls, top and bottom, -a vterminal plate supported at l'each end wall, a strap on one of said plates e'ttending "along a side wall and havingits free end supported thereby, a vc'ont'a'et bntton on 'said free end with its back to said wall, a strap extending from said other plate yover 'and supported by said bottom, a U-shaped spring having its base secured to said last mentioned strap, a second contact bntton intermediate the 'ends o' one of the arms of said spring and supported thereby -in separate but 'confronting' relation to the nrst button, 'a switch oper- 'ator including a knob, a shaft and a 'crank arm, means pivoting the shaft end in 'said bottom, said knob extending through and journalled in l'said top, a spring extending between said crank arm and the housing to provide over-center movement for said switch operator, and spaced lugs eccentrically carried by said operator and straddling the free end of said spring arm to move and hold the latter 'and its contact button in contact-open or contact- 'closed 'position under the action ot' said lover-"cente'r spring.

'2. The switch as defined in claim 1 in which a second terminal plate is arranged at the same 'end wall as that supporting the stationary contact and in turn supports a second stationary contact against the opposite side vWal-l, a'se'condmovable 4contact button on the other arm of said U'shap'e`d spring for lcooperation with said second sta;- tionary contact and a third lug on said operator adapted with one of the previously mentioned lugs to straddle 'and actuate the other spring arm alternatively with vthe tirst.

3. A slow-break, A. C. swich comprising, in combination, a housinghaving side and end walls, top and bottom, a terminal Vplate supported at each end Wall, a strap extending from one of said plates along a side wall and having its free end supported thereby, la contact button on said free endy with its back to said wall, a strap extending from said other plate over and supported by said bottom, a cantilever spring secured to said last mentioned strap, a second contact button intermediate Vthe length of said spring and supported in spaced confronting relation to the rst button, a switch operator including a knob -extending through and os'cillatable in said top, a spring arranged to provide over-center movement for said `switch operator, and spaced lugs eccentrically carried by said operator and straddling the free end 'of said spring arm to move it to contact-open or contact-closed position under the action of said over-center spring.

4. The switch as defined in claim 3 in which the second terminal plate is providedwith anarm extending substantially parallel to and spaced above the bottom supi ported'strap, superposed 'openings in 'said arm 'and 'beftorn supported strap, and in which said over-center spring is of inverted U-shape with one arm journalled in said openings and the other in direct engagement with a crank arm on said switch operator, said arms being biased toward each other by said assembly arrangement to act as a compression spring.

5. A slow-break, A. C. switch comprising, in combination, a closed housing of rectangular conguration, terminal plates oppositely mounted in the housing, a strap on one plate extending along a wall of the housing and having its end supported thereby, a contact button on said end with its back to said wall, a strap extending from the other plate over and supported by another wall of the housing, a cantilever spring arm secured to said last mentioned strap, a second contact button intermediate the length of said spring and supported thereby in separate but confronting relation to the first button, a switch open ator including a knob extending through a wall of said housing for rotation therein, an over-center spring for said operator, and spaced lugs eccentrically carried by said operator and alternatively engageable with the free end of said spring arm to move and hold the latter in contactopen or contact-closed position under the action of said over-center spring.

6. The switch as dened in claim 5 in which said cantilever spring is duplicated and positioned parallel to and spaced from the rst, said second spring having an arcuate, outwardly directed bight substituted for a contact button and engageable with a side wall of the housing when its spring is urged by one of said knob lugs toward contact-closed position whereby this spring resists and stops operator motion resiliently similarly to the first spring.

7. A slow-break, A. C. switch comprising, in combination, a housing having side and end walls, top and bottom, a terminal plate supported at and along each end wall, a strap extending integrally from one of said plates along a side wall and having its free end supported thereby, a contact button on said free end, a strap extending integrally from said other plate over and supported by said bottom, a cantilever spring secured to said last mentioned strap, a second contact button intermediate the length of said spring and supported thereby in spaced confronting relation to the rst button, a switch operator including a knob and a cranked shaft, means pivoting the shaft in the bottom and knob in the top of said housing, said knob extending through said top, a tension coil spring extending between said crank and an abutment in the housing to provide over-center movement for said switch operator, and spaced lugs eccentrically carried by said operator and straddling the free end of said spring arm to move and hold the latter in contact-open or contact-closed position under the action of said over-center spring.

References Cited in the le of this patent UNTED STATES PATENTS Number Name Date 1,200,847 Kaisling Oct. 10, 1916 2,014,474 Hopkins Sept. 17 ,1935 2,203,224 Kimball a June 4, 1940 2,253,968 Cook Aug. 26, 1941 2,254,509 Bassett Sept. 2, 1941 2,293,318 Thirlwell Aug. 18, 1942 2,314,465 Shaw Mar. 23, 1943 

